A surface defect and a performance of a magnetic disk used as an information recording medium have been tested for by a disk tester. The disk tester functions to derive a disk from a non-tested disk cassette storing non-tested disks to be tested, mount the disk on a spindle of the tester, rotate it, test one surface of the disk, reverse the disk by a disk reversing mechanism, test the other surface of the disk and store the tested disk in a tested disk cassette.
In order to efficiently perform disk transportation between spindles and cassettes for non-tested disks and tested disks and a disk reversing, the disk tester of this kind includes various disk transporting devices each using a handling robot. In JP-A-10-143861, one of such disk testers is described. The described disk tester includes a turntable on which a plurality of spindles are arranged, a test stage and a disk reversing mechanism which are arranged around the turntable, where surfaces of a disk can be tested continuously by rotating the turntable by a predetermined angle to reverse the disk.
Further, a disk reversing mechanism for chucking an outer periphery of a disk mounted on a spindle by a chucking mechanism, moving the chucked disk upward from a head of the spindle and rotating the chucked portion by 180° exactly by using an ellipsoidal cam to reverse the disk and then lower the disk to re-mount it on the spindle is described in JP-A-2000-315320.
Incidentally, a hard disk drive (HDD) of 2.5 inches, 1.8 inches and not more than 1.0 inch has been used in various commercial equipment such as automobile products, home electric appliances and audio devices and hard disk drives per se.
The size of the hard disk drive tends to be reduced and the unit cost thereof is lowered. Therefore, manufacturers of hard disk drives are requested to manufacture a large amount of hard disk drives at low cost. In order to accept such a request, it is necessary to provide a compact disk tester which can efficiently test a large amount of hard disk drives.
In order to improve the test efficiency of a disk and downsize the tester, the applicant of this application has filed an invention of a disk test system U.S. patent application Ser. No. 11/513,373 (corresponding to JP-A-2006-260675) in which spindles each for testing one of the surfaces of a disk are provided and the disk is tested by switching the spindles.
In the invention of U.S. application Ser. No. 11/513,373, a disk whose one surface is tested on a first spindle is transported from the first spindle to a second spindle for testing the other surface of the disk while reversing the disk by a disk reversing mechanism during this transportation.
In this case, there is a merit of reversing of the disk during transportation. However, when a disk reversing mechanism described in JP-A-10-143861 or JP-A-2000-315320 is provided, a drive mechanism for reversing the disk, a reversing drive circuit and a transporting device are necessary in addition to a disk chucking mechanism.
Further, in order to downsize the tester, a disk reversing mechanism may be provided on a moving mechanism. However, in such a case, the size of the moving mechanism becomes large and an electrical connection to the disk reversing mechanism and a control of the moving mechanism as well as a timing control in reversing the disk become necessary.